Tag Archives: digital-to-analog converter

BOOK REVIEW: Are you looking for a more complete data converter overview than you get from Converter Passion blog posts or by maintaining your own library of recent papers? Perhaps you’re just wishing to catch up on the latest technology or get a helicopter view to see what’s outside of your own patch in the data converter field? Have you been longing for a contemporary data converter summary that is easy to read, yet rich with technical detail? Read on to know if Advanced Data Converters by Gabriele Manganaro is the book you’ve been looking for.

Book at a glance

Advanced Data Converters is not the regular tech tome. The actual content only spans slightly more than two hundred pages, followed by a comprehensive reference section listing over 400 relevant works. Of the five chapters, two are introductory in nature, and the remaining three respectively covers ADC, DAC and Trends. On first glance this made me wonder if there was actually anything in the book. Don’t worry, though. Advanced Data Converters is a masterpiece of lossless information compression that may even go beyond the limits of information theory as we know it 🙂

Let me say right from the start that this is a really good book. The author is clearly a gifted writer and has delivered a text that simply flows. It reads more like an interesting story than a technical lecture. Although the topic is advanced, the form never gets in the way. It is concise, professional in style, yet sufficiently relaxed and easy on the brain. Most of us can appreciate what an achievement that is.

Key chapters

The chapter on A/D converters includes a review of underused classic architectures now brought back into the game to overcome the challenges imposed by CMOS scaling. Time-interleaving, calibration, and emerging architectures and techniques – often introduced for the same reason – are also discussed. The story told in this chapter is so in tune with what I’ve observed through my own survey that I actually don’t have a single suggestion as to what could have been added or taken out. It is indeed a very accurate and insightful description of how the field has developed lately. The number of different architectures and techniques covered in a relatively limited space is truly impressive.

A slightly different approach was used in the D/A converter chapter, where “precision” DACs where left out in favor of current-steering DACs. Instead, these are given a more thorough treatment – essentially you get a complete rundown on the key design issues for this type of DAC. This worked very well for me. Ending the chapter is an update on the latest developments on high-performance and specialized DACs.

Finally, there’s a chapter on data converter trends. As the faithful Converter Passion reader may suspect, I’m not easily impressed with scatter plots and survey data trends. Quite unsurprisingly, this is the chapter where I’m instantly itching to jump into the discussion, add a few graphs, discuss what the plots actually show, etc. That’s not necessarily a bad thing, though. Just as the previous two chapters inspire the reader to look deeper into emerging ADC/DAC architectures, it is a good thing if this chapter encourages the reader to become a more active and educated user of survey data. Analogous to the rest of the book, the author has managed to collect an impressive amount of information in a very limited space. The ADC part is split between a summary of several surveys by other authors, and some original work using the Murmann data set. The DAC part reflects the present lack of any large DAC survey, and therefore the trends are estimated from a very small set of data.

The more color, the better …

The book as a whole

Advanced Data Converters does not start from scratch, but from a point where the reader is assumed to be familiar with the basics of data conversion, sampling, signal processing and IC design. There are numerous references to where the basics are treated, and even if the level is “advanced”, it never gets scary or impenetrable. If you’re relatively new to the field, you could very well enjoy the book anyway.

For more senior scientist, designers, or data converter end users, the book is a veritable goldmine of information. It successfully captures just about everything necessary to catch up with the latest data converter developments. It allows you to understand the essential technical issues and driving forces that shape the data converter field. None of the topics are treated in great depth, but the amount and quality of references for further reading is impressive. The book delivers a feature-rich helicopter view of the entire data converter field that encourages further exploration. It also provides you with a solid framework – a “grid of knowledge” – in which you can place your own bits and pieces as you pick them up.

This is not a book that will bypass the 6–8 years it is said to take becoming a reasonably good data converter IC designer. Neither will any other book. But keeping it as a companion will probably ease the pain of those years considerably. It will also make the constantly changing data converter landscape a bit less confusing. This book is both educational and a source of inspiration for new adventures to all of us that feel we have more to learn. If you truly believe you know it all, then it might still be worth buying it solely for the excellent list of references.

You can probably guess by now, what the rating will be. Since this is the first book review on Converter Passion, I had made a firm decision to save some headroom at the upper end of the full-scale range. That was the plan. But Advanced Data Converters is one of the best written tech books I’ve ever read, so it would not be correct to give it anything but the highest grade – 5 out of 5.

BTW: If your grandmother gave you money for Christmas, this book might be what she had in mind 😉

Converter Passion will try to plant some seeds of data converter knowledge

Hi all, and my sincere apologies for not posting for a while. I’ve had some rather intense family emergencies that kept me out of the blogosphere for a few months. Slightly wiser from the experience, I want to be careful to not promise too much in terms of blog activity, but the current plan is to resurface more seriously after the upcoming holidays and the New Year.

One of the activities I’ve planned is to list useful data converter resources on the web. First out could be recommended literature for those wanting to catch up on the basics [whatever that may be]. I’ve been contemplating making these lists for some time now, but was re-inspired by the app note/report A Glossary of Analog-to-Digital Specifications and Performance Characteristics highlighted in a recent TI newsletter. It doesn’t have to be just app notes, but it should be resources that are completely open and freely available – preferably without any registration procedures. So please e-mail me, or post a comment here with your suggestions for the best internet resources for anyone new to the field.

Being a bit old-school, I still do read books 😉 so a parallel activity will be to compile a list of good books on data conversion, data converter design & application and related topics – from entry level to the most advanced treatment. Please tell me which books you’d like to recommend, and if you feel like it you can also provide a brief review of 2–200 words describing what you like about it.

As always: Don’t be shy to promote your own work, your company or any one else you wish to give your unreserved praise. All the readers of Converter Passion are of the generous, happy type (I hope). And if you happen to have a data converter book coming out soon, let us know about it too. I’ll be more than happy to highlight it, and if you send me a copy of the final product I’ll also read it and post a book review here on the blog.

I’m completely in love with Italy now. It was my first time there, and I was impressed by just about every aspect of the visit – the beautiful landscape, the fascinating history embodied in ancient buildings, and of course by the people. Perhaps it was accentuated by me going through the “vanilla phase” with Italy, but it did seem very easy to get a kind smile from just about any Italian I met throughout the entire trip.

A fraction of the big happy family of IWADC delegates

Attending IWADC 2011 was every bit as pleasant: The conference itself ran like clockwork, the medieval city of Orvieto was a decidedly pretty conference location, and the relatively small size of the conference contributed to the relaxed and friendly character of the event. Almost like a family event – a big happy Italian family, I could imagine :-). The feeling of being welcome and surrounded by “family” was very much accentuated by the hospitality shown by the conference general chair, professor Paolo Carbone (University of Perugia), members of the organizing committee, and other delegates. During the conference dinner when we were also treated with one tasty Italian dish after another, I remember uttering something like “all conferences should be in Italy”. That’s how good it felt to be there.

Who doesn’t love Italian food? I was late to some sessions because I tried to eat all the Salatini before they cleared the tables …

CWCP winner

A winner: Yu Lin

Now being a solid tradition, each conference I attend needs to have an opportunity to connect with Converter Passion. To motivate conference delegates to not be shy we came up with the Connect with Converter Passion (CWCP) prize. The rules are simple: First blog reader to find me at the conference and claim the prize is the winner, and for IWADC 2011 the winner is Yu Lin, a PhD student at Technical University of Eindhoven who was also presenting the paper “An Input Signal Statistics Aware Design Approach and Examples for Analog-to-Digital Converters for communication systems” at the conference [co-authors: Kostas Doris (NXP), Hans Hegt and Arthur van Roermund (TU Eindhoven)]. It was a pleasure to meet such a motivated blog reader. Yu aimed for victory and did not hesitate to claim the prize already at the informal pre-conference reception at restaurant Maurizio. Definitely the right spirit and a worthy winner indeed. Congratulations! Normally, the competition is only for the glory, but this time a small surprise memento was added in the form of a handmade key ring in black leather produced by “Boothill Bob” from Boothill Bob Holsters.

The conference

IWADC covers ADC modeling, testing and data converter analysis and design. Because it is an IMEKO conference, various aspects of measurement becomes a natural thread in many contributions, although the scope is rather wide. It includes calibration of ADCs and error correction of the ADC output, such as presented in the papers “Digital background calibration of subsampling time-interleaved ADCs” by Centurelli from Università di Roma la Sapienza, and “A Linearization Strategy for Undersampling Analog-to-Digital Converters” by Vallant from Cassidian Electronics. Time-to-Digital Converters (TDC) seems to be a growing field, and a fair number of papers addressed various aspects of TDCs, for example “Modeling Noise Effects in Time-to-Digital Converters” by Napolitano, University of Perugia, and “Time-to-Digital Converter (TDC) with Sub-ps-Level Resolution using Current DAC and Digitally Controllable Load Capacitor ” by Alahdab from University of Oulu. There were classic ADC implementation papers such as “A 6-bit 3GS/s Flash ADC in Bipolar 0.25 um for the radiotelescope SKA” by Da Silva from Station de Radioastronomie de Nançay, and I personally found it interesting to hear about ADC implementations in emerging materials, as in “ADC Design in Organic Thin-Film Electronics Technology on Plastic Foil” by Marien of K. U. Leuven.

Scientific discussions

Of my own contributions, the first (An empirical approach to finding energy efficient ADC architectures) was about using the measured performance of chips made by others to better optimize your own design, and the second (Using Figures-of-Merit to Evaluate Measured A/D-Converter Performance) treated how to assess the quality of figures-of-merit often used to make comparisons of measured performance.

IWADC face recognition

There were many more papers presented at the conference, but I don’t intend to walk you through the entire program. Note also that I have mostly mentioned the first authors above although most papers have one or more co-authors. Please add comments below and tell us about any papers, co-authors or delegates that you wish to mention. Or just say hi, and let everybody know you were there too. Share the name of your contribution, and your impressions from the conference with us.

Yes, I was there. Here together with publication chair, Dr. Antonio Moschitta (left) and general chair, professor Paolo Carbone (right).

To round it off, I’ve made a pie chart of the distribution of delegates between countries, based on statistics provided by professor Carbone. As could be expected, the Italian representation was strong. The rest of the countries are quite evenly represented. As you can see, delegates came from both USA and China, although the vast majority were from European countries.

Distribution of IWADC 2011 delegates by country

Please post your comments below if there is anything you’d like to add about the conference.

After being lost in the world of Converters for a while, I always have this fundamental question as follows:-

Industries, Publications always talk about GSamples/sec of an ADC or a DAC and the higher the rate, better the converter is. But very few talk about the Bandwidth in the title of the ADC. Even in publications, I always see the title as ” An XGsamples/sec ADC” where as I think it should be “An X Gsamples/sec Y Mhz BW ADC” since many of these converters do not retain performance up to Nyquist.

Even when looking at the TI ADC’s I need to search the data sheet to find the real bandwidth of the ADC. Shouldn’t the sample rate and BW be always reported together so that one quickly understands what the capabilities of the ADC are?

Could you comment on this?

Thanks,
Ameya

Good question Ameya, and one that touches on a broader topic (scientific reporting practices) that I’ve been planning to bring up for a while. This is a good starting point. Perhaps your question was mostly concerning data sheets? Either way, I’d like to broaden it to include scientific papers as well.

So blog readers, what do you think?

Is there an inflation in paper/data-sheet titles?

Should we require paper titles to more accurately describe the actual bandwidth of the ADC?

Is effective resolution bandwidth (ERBW) the best measure?

If there is an inflation, and a practice to boost performance in the titles, what will happen to the pioneers which put more complete (potentially less impressive) information in the titles? Rejected papers and loss of business? Is the target audience really that gullible? Don’t they read the content of a data sheet or paper? How long can a paper/data-sheet title be 😉 … etc.

… and I felt it deserved a dedicated post where you can all have your say. So, what do you all think? And what other companies have you heard of? Do you even agree with steve that it is these six that dominate? If not, who are?

Edit: I’ll be working on the list(s) below, trying to get it as complete as I possibly can. With your help it should work. Just keep suggesting data converter companies to add here. My proposal is to limit the list to companies that provide stand-alone data converters and/or data converter IP. Companies providing data-converter related design services and expert consulting could of course be interesting too, and perhaps go into a second list. [That way I can include my own company, ADMS Design too 😉 ]

Edit 2011-04-09: As you might have heard, Texas Instruments is to acquire National Semiconductor. Read more about it here.

And then there were only five … 😉

The “Big Six”

As the question was asked by steve, we get the following list of six US data converter companies – dubbed the “Big Six” by jjwikner below – that (supposedly) dominate the ADC and DAC market. Here in alphabetical order:

The list is not written in stone. Have your say below. Should it be the big 3, 4, 5, 7 instead? How about data converter IP dominance – is that a completely different list of companies? And don’t forget the original question: why are all of these companies US-based? Something in the US water? Engineering tradition? Business culture? Choice of target applications? Are the leading Asian companies keeping their designs for in-house use, or did they simply bypass the stand-alone converter phase altogether? Are they now positioning themselves for the inevitable embedded data converter era by developing IP blocks for SoC designs?

The complete list?

To the best of my knowledge, and with the kind help of my blog readers, this is the “complete list” (*) of companies offering data converter IP or stand-alone parts. Again, in alphabetical order, and with the Big Six included:

(*) Allow the list a reasonable settling time constant, and please send me an email or post a comment below if you know of any company not included in the list, or have any other remarks.

NB: I have not necessarily made an assessment of the individual companies included in the list, and the list is therefore no statement of the quality or suitability of the products/IP offered for a particular purpose, nor an endorsement of the company itself.

The list seems very US and Euro-centric, but that’s my current horizon. I’m sure there must be some Asian companies out there. Scientific activity actually suggests that Asia is going to take over this business eventually. So, please enlighten me! Where are those Asian companies?